Development And Properties Of Foamed Concrete With Fiber Reinforcement

A fiber reinforced foamed concrete was developed that contains polypropylene fibers, alkali-resistant glass fibers or high strength and high modulus of elasticity Polyvinyl Alcohol (PVA) fibers. The influence of material factors, such as fiber volume fractions, water-cement ratio and sand fineness, on the properties of foamed concrete which includes density, strength, deformation and thermal conductivity, were investigated. The parameters of pore structure, such as pore porosity, pore area, pore diameter, pore morphology and pore position, were measured with image processing systems, and the relations between pore structure and the properties were analyzed.When the water-cement ratio increases from 0.5 to 0.75, the density of foamed concrete is decreased; the porosity and pore diameter are increased; the pore morphology is improved; the strength and thermal conductivity are decreased accordingly. Grinded sand can be used to reduce the pore diameter, and improve pore morphology. The three fibers can reduce foam breakage and enhance the stability of fresh foamed concrete. So the density and pore diameter of fiber foamed concrete decrease, and porosity increases. And the three fibers also can improve pore morphology. When the foam volume remain the same, the strength and thermal conductivity decrease with the fiber volume fraction increases as a result of the increase in porosity. But when the density of fiber foamed concrete are the same, the fibers can enhance the flexural-tensile strength of foamed concrete except polypropylene fibers. When the glass fiber volume fraction is 1.6%, the flexural-tensile strength increases by 143%, and its flexural toughness index is enhanced by 8.1 times, while the thermal conductivity keeps little change. Moreover, the three fibers decrease the dry shrinkage of foamed concrete.The results show that incorporating certain types and quantities of fiber can optimize the structure and overcome the deficiencies of foamed concrete to get a wall material with integrated high-performance.